Recent medical technology is focusing more and more on producing 3D reconstructions of the organs of the body of a human or animal patient, since spatial representation substantially improves diagnosis possibilities. One condition for a corresponding high-quality three-dimensional representation is however that the organs do not move during the image recording. To be able to produce a 3D reconstruction of a periodically moving object, the image recording must be synchronized with the movement of the object.
US 2005/0058248 A1 describes a method for mapping an organ by means of a recording device rotating through an angle. With this method, an image recording system, e.g. an angiographic x-ray C-arm, is moved once around the patient in a rotary motion of less than 360°. The rotational speed of the rotating recording device is modulated here as a function of a reference signal, which can be an ECG signal for instance. Accordingly, the recording device is not moved at a constant speed, but is accelerated and slowed down synchronously with the heartbeat, so that the recording system is moved as quickly as possible during the phase of the cardiac cycle which is of interest but is moved as slowly as possible during the remaining phases of the cardiac cycle. This method makes heavy demands on the mechanics and control system of the examination apparatus.
DE 196 27 166 A1 discloses an x-ray computed tomography device with an x-ray tube and a detector, which rotate completely, in some instances several times in one direction, at constant speed around an object to be scanned, in order to acquire data only during specific phase segments of the movement of the object. A period and a phase are detected from R-waves in an electro-cardiographic signal.